Many diseases that are primarily inflammatory in nature, (for example, rheumatoid arthritis, inflammatory bowel diseases, systemic lupus erythematosis, and asthma) or that have a major inflammatory component, are treated with steroids such as prednisone. In addition, some cancers are treated with steroids, and transplant patients also receive steroids to prevent transplant rejection. However, the effectiveness of steroid treatment varies from patient to patient and is usually impossible to predict. Some patients may be constitutively non-responsive to a particular medication, and others may become refractory to treatment over time. In some cases, patients may experience symptomatic relief, but attempts to withdraw therapy lead to disease flare. As a consequence, the inclination for doctors to continue steroid therapy and even to increase the dosage of a steroid is associated with serious, cumulatively debilitating, side effects. The clinical screening of patients who are candidates for steroid therapy for their ability to respond to steroids and the monitoring of patients who are undergoing steroid therapy but who may be transitioning from steroid responder to non-responder (i.e., refractory) status is therefore of significant clinical importance.
A need therefore exists for a diagnostic assay or test for drug, e.g., steroid responsiveness.